Rotary kiln



April 9, 1929- J. 5. FASTING ROTARY KILN Filed Jan. 6; 1926 2Sheets-Sheet 1 IN l/EN 70R W M QM J. S. FASTING ROTARY KILN April 9,1929.

Filed Jan.6, 1926 2 Sheets-Sheet 2 INVENTOR J V ,M%@

I Patented Apr. 9, 192 9.

UNITED STATES .PATENT OFFICE.

J'OHAN SIGISMUND FA STING. OF VALBY, NEAR COPENHAGEN, DENMARK, ASSIGNOR.

. TO F. L. SMIDTH 00.,- OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

ROTARY KILN.

Application filed January 6', 1926, Serial No. 79,509, and in GreatBritain January 7, 1925.-

In rotary kilns, such as are used in the manufacture of cement, thereare frequently insorted in the kilns near the feed end, metal members,such as cross plates or lifters or chains, for the purpose of promotingthe travel of the material through the kiln or of increasing the surfacecontact of the material with the hot combustion gases to promote thedrying or the heating of the material. The

10 temperature of the combustion gases is usually so intense, however,that such metal members are subject to rapid deterioration. Inaccordance with the present invention it has been found that thisdisadvantage .can be 1 overcome and a reasonable life assured for suchmetal members by reducing the temperature of the combustion gases in thekilns, in the zones where such metal members are located, by theintroduction into the kilns,

below such zones, of a relatively cool gaseous bod such as air or evenrelatively cooler stac gases. Preferably atmospheric air, which is notcharged with moisture taken up from wet raw material, as might be thecase with stack gases, is employed and means are also preferablyprovided whereby such atmospheric air shall be heated somewhat before itis introduced into the kiln iii-order to avoid the great reduction oftemperature within the kiln. Means are also preferably provided wherebymay be regulated the volume of the relatively cool air to be admitted.

It will be understood that the particular form of means employed in thepractice of the invention may be varied greatly according to theconvenience of the manufacturer of the kiln or of the cementmanufacturer and the conditions of use. In the-accompanying drawings, inwhich are illustrated two embodiments of the invention:

Figure 1 is a view partly in section and partly in elevation of a. kilnadapted for introduction of unheated atmospheric air below the heatingand drying zone. v

Figure 2 is a detail view in section on the broken line 2-2 of Figure1.. I

Figure 3 is a view partly in section and or heating the air beforeadmission to the kiln. I

Figure 4 is a detail view in longitudinal sectional elevation and on alarger scale of the means indicated in Figure 1 for regulating theadmission of air.

Figures 1, 2 and 4, through which, in the con- 7 cool by the passagethrough it of the tively cool air and at the same time is heated partlyin elevation of a kiln with provisions Figure 5 is a detail view partlyin section.

and partly in elevation and on a larger scale of the means indicated inFigure 3 for regulating the admission of air.

Except as hereinafter explained, the rotary kiln a may be of any usualor suitable construction, provided at its lower or discharge end, as atb, with means for the supplying of fuel for combustion in the kiln, andat its upper or feed end with means indicated at c for the feeding ofthe material to be treated, the upper end of the kiln entering,as-usual, a dust chamber d. As shown in Figure 1, the kiln may beprovided near its upper or feed end, in the heating and drying zone,with cross plates 6 of metal, which form longitudinal channels withinthe kiln in which the material is distributed, in order that it may bemore effectively dried and heated through contact with the combustiongases which pass through the kiln and the dust chamber and thence intothe usual stack, not shown. Such metal members as the cross plates e orother metal members, when subjected to the intense heatof theuntemper'ed combustion gases, de-

teriorate somewhat rapidly and must be reso newed from time to time,involving the stopping of the operation of the kiln. To obviate thisdifiiculty openings are provided through the kiln wall, as indicatedgenerally at f in struction represented in these figures, atmosphericair is admitted at a point below the heating and drying zone of thekiln, in which are located the metal members 6. In order to prevent theescape of cement material fromthe kiln through such openings and inorder also that the relativelv cool air may be admitted to the kihi nearits axis ratherthan close to the wall, the air is admitted through atubular conduit g, disposed diametrically through the wall of the kiln,with its open ends outside the wall and provided with an opening 9- nearthe axis of the kiln and directed toward the upper or feed end of thekiln. This conduit is itself kept relatively 10o relaby the combustiongases to some extent sothat the air admitted is itself somewhat heat edand too great reduction of temperature in the kiln is prevented. I

.It is desirable that the volume of relatively cool air admitted shallbe capable of regulation according to the conditions of operation of thekiln and there is therefore provided for the opening g a valve h whichmay be carried by a rod k pivoted at oneen'd, as at If, in the conduit 9and provided at the other end, as at h with a latch for engagement witha rack 72, so that the valve k can be held in such position with respectto the opening g as toiadmit so much air as may be found desirable. I

The construction shown in Figures 3 and *5 is generally similar to thatshown in Figures 1, 2 aud t, but difiers in details now to be described.In this embodiment of the invention provision is made for the heating ofthe air before its introduction into the kiln at a point below thedrying and heating zone. Al-.

though the air is heated, it will be understood that its temperature islow as compared with the temperature within the kiln at the point wherethe air is admitted and that the effect is to reduce the temperature inthe heating and drying zone to a point below that by which the metalmembers in that zone would be caused to deteriorate rapidly. As show inFigure 3', a staionary shell 11 is placd around the portion of the kilnwithin which is the burning zone, such shell being open atits lower endand connected -by a suitable conduit a" with a stationary shell 71 whichsurrounds the kiln at the point where the openings f are provided, sothat heated air iscontinuously supplied to the chamber 11 such heatedair, however, being relatively cool .as compared with the normaltemperature of the combustion', gases within the kiln at that point. Adiametrically disposed tubular conduit g,

' having open ends and with a central opening g directed toward theupper end of the kiln and also with a valve h to control the admis-..

sion of the relatively cooler air, is provided substantially as alreadydescribed with respect to Figure 3, but with special provision forcontrolling the position of the valve, necessitated by the provision ofthe fixed shell '5 In this construction, shown in detail in Figure 5,the pivoted rod h which carries the valve h, is provided at its lowerend with a roller k which is received in a U section ring is. The latteris supported within the shell i so as to be capable of adjustment in anaxial direction, but is preferably not rotatable within the shell. Ablock 70 in which the ring is is seated is engaged by a screw 70 whichis carried by a stationary nut k and has outside the shell 71 anoperating head. or handle 70. Movement of the ring Join an axialdirection,

by manipulation of the screw 70 causes movement of the valve h toward.or from the opening 9 to regulate the admission of the relativelycooling air.

changes can be made in the form and character of the devices foradmitting and regulating the flow of the relatively cooling'air, as wellas of the provisions for heating the air somewhat before it is admittedto the kiln.

' I claimas my invention:

1. The combination of a rotary kiln having metallic members near itsfeed end and extending inwardly away from the lining and provided withan opening adjacent the metal- 'lic members for the introduction of airat a point adjacent the metallic members in the direction of thedischarge end, a stationary shell surrounding the discharge end of thekiln to form an air heating chamber,.a second stationaryshell'surrounding the kiln intermediate the feed and discharge end andforming a chamber for communication with the opening in the kiln, aconduit connecting said chambers, means to introduce air into the kilnfrom the second chamber, means to direct the air so introduced towardthe feed end of the kiln and upon the metallic members, and means tocontrol the flow of the air.

2. The combination of a rotary kiln having metallic members near itsfeed end and ex tending inwardly away from the lining and provided withan opening adjacent the metallic members for the introduction of air ata point adjacent vthe metallic members in the direction of thedischargeend, a stationary shell surrounding the discharge end of thekiln to form an air heating chamber, a secthe opening in the kiln, aconduit connectin said chambers, a tubular conduit mounte within thekiln and communicating with the opening therein, an opening in theconduit within the kilndirected toward the feed end thereof to directthe air toward the feed end and upon the metallic members, a valve forthe opening in said conduit, a pivoted rod carrying the valve and havingan end outside the kiln, a section ring within the second chamber andengaged by the end of said rod, and means to move the ring in an axialdirection.

This specification signed this 15th day of December, A. D. 1925. Y

JOHAN SIGISMUND FASTING.

